The present invention relates to intraluminal catheters and devices. More specifically, the present invention relates to a device for actuating an intraluminal device. Intraluminal catheters and devices are currently employed in a variety of medical procedures. These procedures often require manipulation (or actuation) of the intraluminal device by a mechanism located outside of the patient""s body. This invention relates to such devices which may be employed in a number of such procedures.
Catheters have long been used in intraluminal procedures for various medical needs. They generally are made from elongated tubes which may be placed within various body lumens. A common use for catheters is the treatment of vascular diseases. In such treatment, a catheter is inserted into a body vessel such as an artery. The catheter is then advanced through the artery to the site of the disease where treatment is performed.
A wide variety of treatments are currently available using different devices and mechanism delivered with or within, such catheters. For example, a stent or graft may be delivered to the site of a diseased artery and deployed within the artery. Other treatments employ the expanding of balloons (as in angioplasty) or delivery of drugs to treat arteries. Importantly, the treatment at the intraluminal site typically requires the manipulation of the catheter system external to the patient""s body. That is, a physician-operator must actuate the catheter system into performing the intraluminal treatment by the use of devices which remain outside the patient""s body. These devices are connected to the catheter system and are able to perform the treatment at the intraluminal site.
Certain medical terms regarding the orientation of medical devices are useful for a complete understanding of these devices. The term xe2x80x9cdistalxe2x80x9d typically refers to a direction away from the operator of the device. Thus, the distal end of the catheter is inserted into the body and advanced distally through the vascular system. The term xe2x80x9cproximalxe2x80x9d typically refers to a direction towards the operator of the device. Thus, the proximal end of the catheter remains outside of the body and the catheter is withdrawn proximally to be removed from the body. These terms will be used herein for consistency.
An example of a known intraluminal procedure is the delivery of a self-expanding stent to the site of a stenosis (the narrowing of an artery due to vascular disease). Self-expanding stents typically employ spring forces which expand the stent radially outward to contact the arterial wall and maintain the arterial lumen in an expanded state. Typically, such a stent is mounted onto a catheter, collapsed to a smaller diameter and contained within a sheath for delivery. For deployment, the physician-operator may retract the sheath to expose the stent to allow it to expand for treatment. This may be accomplished by using a variety of actuator mechanisms connected to the proximal end of the catheter.
The actuator mechanism may be as simple as a knob independently attached to the catheter sheath. As the physician-operator pulls the knob proximally, the sheath withdraws proximally. Such a direct connection usually allows the physician some amount of control over the intraluminal procedure. Therefore, a direct controlling mechanism for performing the intraluminal procedure may be a preferred aspect of a catheter system.
As in the example described above, some intraluminal procedures require the retraction of sheaths, wires and the like while the main catheter remains stationary. Some procedures also require the advancement of similar devices. Simple solutions have been developed, such as attaching a knob, pull, or lever to the device requiring advancement or withdrawal. This allows some direct control by the physician-operator within, of course, certain limits.
One limitation in the use of a direct control device has been the distance required for advancing or retracting the device. As the distance increases, direct control of the device may become awkward or cumbersome. That is, a physician-operator may find it difficult to manipulate the control device over several inches while maintaining the remainder of the catheter system stationary.
Solutions to this problem include the use of pistol-grip handles with ratchet triggers. When one squeezes the trigger, the catheter system is actuated a certain distance, whereas releasing the trigger does not cause any further actuation. Thus, the catheter system can be repeatedly actuated in a single direction by repeatedly squeezing and releasing the trigger. These devices, however, do not provide direct control of the procedure. The squeezing of the trigger usually does not impart movement in the intraluminal device in one-to-one correspondence. Thus, a triggering mechanism inherently replaces the direct control by the physician with a mechanical relaying of control.
What has been needed is a mechanical device which allows direct manipulation of an intraluminal medical device that requires a lengthy displacement. The present invention satisfies these and other needs.
The present invention relates to a device for actuation of an intraluminal catheter system. More precisely, the present invention consists of a ratcheting handle which enables the actuation of an intraluminal catheter system in a direct correlation of transmitted motion, even when a large relative motion is required. The present invention includes a stationary base, a slidable pull back trigger or handle, a ratcheting system and a connection to the catheter system to create an overall intraluminal catheter system.
The present invention may enable actuation of a variety of intraluminal catheter systems. These systems, in turn, provide a variety of treatments. Known intraluminal treatments include, among others, vessel occlusion, angioplasty and the implantation of stents and grafts. Stents are intraluminal prosthesis which are implanted to expand and maintain the patency of body vessels. Grafts are also intraluminal prosthesis which may be used to replace body vessels or to isolate diseased vessels from the flow of blood.
Intraluminal treatments typically require actuation of the catheter system for treatment. For instance, in the implantation of a self-expanding stent, a sheath may be required to be retracted to allow the delivered stent to expand. When a particularly long stent is to be implanted, the sheath may be required to be retracted a greater distance than a physician-operator feels comfortable retracting in a single motion. The present invention provides a device to retract a sheath the required distance without requiring excessive manipulation by the physician-operator.
The present invention is configured to allow direct manipulation of the catheter system without a mechanical interface. Direct manipulation of the catheter system usually allows the physician the maximum amount of control over the intraluminal procedure. Thus, in the example described above, in which a sheath is retracted, the device of the present invention enables the physician to perform the procedure at an intraluminal site with directly corresponding motions. That is, as the physician withdraws the slidable pull-back trigger along the base, the sheath is retracted a corresponding distance at the intraluminal site. Since this device is in-line with, and directly connected to, the catheter system, the physician""s motions directly correspond to the motion of the sheath.
The present invention also permits the direct actuation of catheter systems when the required retraction or motion is greater than a physician may feel comfortable in performing in a single motion. Thus, in the example of the delivery of a long self-expanding stent, the present invention permits the direct manipulation of the retractable sheath albeit in multiple motions. In such a procedure the physician may withdraw the pull-back trigger the length of the base, which may only correspond to a portion of the motion required to withdraw the sheath to expand the stent. The physician may then advance the pull-back trigger, leaving the remainder of the catheter system, including the sheath, stationary. The physician may then withdraw the pull-back trigger again which withdraws the sheath an equivalent amount. This procedure may be repeated multiple times until the sheath is fully withdrawn and the stent expanded. Although reference herein is made to the withdrawal of a sheath for the deployment of a self-expanding stent, those of skill in the art will recognize that this device can be capable of performing a variety of functions with other medical devices and in other medical procedures.
The base of the present invention connects to the catheter system in a fixed manner. The proximal end of the catheter connects directly to the distal end of the base. The physician may use the base to advance or withdraw the catheter system within the patient""s body. The base may be further configured to provide for the functions of the catheter system. For example, the base may include a guide wire port on the distal end of the base which provides access for a guide wire extending through the base and catheter system. The base may also include flush ports for flushing the system, and thumb-rests to facilitate manual actuation of the catheter system. Furthermore, the bottom side of the base may be configured to securely rest on a curved surface such as a patient""s leg, for example, when a femoral approach is used.
An actuating device is slidably disposed within the base. This actuating device includes the pull-back trigger and a set of ratchet teeth. The pull-back trigger (or simply the xe2x80x9cpullxe2x80x9d) may be alternatively configured as a knob, a trigger, a lever or simply as a bar. Even though the term xe2x80x9cpull-back triggerxe2x80x9d is used herein, it should be recognized that this actuating device may also be pushed or slid in some other manner. The operative requirement of the pull-back trigger is that it can be manually grasped for sliding both proximally and distally along the base. Furthermore, the actuating device may include a pair of pull-back triggers which will allow the physician-operator to use two or more fingers to operate the device.
A set of ratchet teeth is connected to the pull-back trigger such that they slide proximally and distally with the pull-back trigger. If the desired function of the device is the proximal withdrawal of some article (such as a sheath) the teeth should face proximally. To face proximally, the ratchet teeth each have a sloping surface and a proximal facing horizontal surface. This horizontal surface is configured to engage a corresponding surface of distal facing ratchet teeth. The sloping surface is configured to slide over the corresponding surfaces of distal facing ratchet teeth. If the desired function of the device is the distal advancement of some article, then the teeth should face distally with the surfaces reversed.
A slider mechanism is also disposed within the base and includes at least on ratchet tooth correspondingly engaged with the set of ratchet teeth on the actuating device. The slider is connected to that portion of the intraluminal catheter system that is actuated. Thus, in the example described above, the slider attaches directly to the sheath.
The slider, actuating device and base may be configured such that the actuating device is withdrawn as the slider is withdrawn. Since the slider is directly connected to the part of the catheter system requiring actuation, that part of the system is likewise withdrawn. Due to the configuration of the ratcheting teeth, the slider is not advanced as the actuating device is advanced. Thus, through repetitive withdrawing and advancing of the actuating device the slider can be withdrawn repeatedly without being advanced. This, in turn, actuates the movable portion of the catheter system in discreet steps, which can be repeated to actuate that portion a greater distance than one motion might allow.
The base may also include a separate top portion which covers at least the slider and ratcheting teeth of the actuating device. The top portion may be fixedly secured to the base so that the top does not move with either the slider or actuating device. Furthermore, the top portion may include a set of ratcheting teeth with the same orientation as those on the actuating device. When combined with at least one corresponding tooth on the top of the slider, this set of ratcheting teeth securedly prevent the slider from advancing distally as the actuating device is advanced.
A slot may be included through the top portion to allow visualization of the slider. In this manner, the physician-operator may monitor the amount of withdrawal or advancement of the actuating portion of the catheter system. The slot may also be used to manually depress the slider to disengage the ratcheting teeth of the slider and top portion. When the slider is disengaged from the top portion, the slider and actuating device may be advanced forward in unison, thus allowing a motion of the slider which is otherwise precluded by the ratcheting system. This may be useful, for example, in repositioning a sheath after it has been partially withdrawn.
The advantages of the present invention will become apparent from the following detailed description thereof when taken in conjunction with the accompanying exemplary drawings. Those of skill in the art will recognize that variations are possible to the described preferred embodiments while remaining within the scope of the invention. Thus, the following descriptions are not intended to limit the scope of the invention which is to be defined by the claims.